Search results for "Noctuidae"
showing 10 items of 28 documents
Effects of ajugarins and related neoclerodane diterpenoids on feeding behaviour of Leptinotarsa decemlineata and Spodoptera exigua larvae
2001
Three naturally occurring ajugarins and seven semisynthetic derivatives of them, possessing different functionalities in the decalin part, together with two natural furoneoclerodane diterpenes, have been assessed as feeding behavior modifying agents of larvae of the generalist Spodoptera exigua and a specialist like Leptinotarsa decemlineata. Ajugarin I and some of its derivatives exhibited a significant antifeedant activity against larvae of S. exigua in both choice and no-choice assays. Conversely, the furoneoclerodane diterpenes only presented antifeedant activity against larvae of L. decemlineata. These results indicate that the biological action of the tested substances is strongly mod…
Genetic variability of Spodoptera frugiperda Smith (Lepidoptera: Noctuidae) populations from Latin America is associated with variations in susceptib…
2006
ABSTRACT Bacillus thuringiensis strains isolated from Latin American soil samples that showed toxicity against three Spodoptera frugiperda populations from different geographical areas (Mexico, Colombia, and Brazil) were characterized on the basis of their insecticidal activity, crystal morphology, sodium dodecyl sulfate-polyacrylamide gel electrophoresis of parasporal crystals, plasmid profiles, and cry gene content. We found that the different S. frugiperda populations display different susceptibilities to the selected B. thuringiensis strains and also to pure preparations of Cry1B, Cry1C, and Cry1D toxins. Binding assays performed with pure toxin demonstrated that the differences in the …
Bacillus thuringiensis Vip3Aa Toxin Resistance in Heliothis virescens (Lepidoptera: Noctuidae)
2017
ABSTRACT Laboratory selection with Vip3Aa of a field-derived population of Heliothis virescens produced >2,040-fold resistance in 12 generations of selection. The Vip3Aa-selected (Vip-Sel)-resistant population showed little cross-resistance to Cry1Ab and no cross-resistance to Cry1Ac. Resistance was unstable after 15 generations without exposure to the toxin. F 1 reciprocal crosses between Vip3Aa-unselected (Vip-Unsel) and Vip-Sel insects indicated a strong paternal influence on the inheritance of resistance. Resistance ranged from almost completely recessive (mean degree of dominance [ h ] = 0.04 if the resistant parent was female) to incompletely dominant (mean h = 0.53 if the resistan…
Use of Bacillus thuringiensis toxins for control of the cotton pest earias insulana (Boisd.) (Lepidoptera: Noctuidae)
2006
ABSTRACT Thirteen of the most common lepidopteran-specific Cry proteins of Bacillus thuringiensis have been tested for their efficacy against newly hatched larvae of two populations of the spiny bollworm, Earias insulana . At a concentration of 100 μg of toxin per milliliter of artificial diet, six Cry toxins (Cry1Ca, Cry1Ea, Cry1Fa, Cry1Ja, Cry2Aa, and Cry2Ab) were not toxic at all. Cry1Aa, Cry1Ja, and Cry2Aa did not cause mortality but caused significant inhibition of growth. The other Cry toxins (Cry1Ab, Cry1Ac, Cry1Ba, Cry1Da, Cry1Ia, and Cry9Ca) were toxic to E. insulana larvae. The 50% lethal concentration values of these toxins ranged from 0.39 to 21.13 μg/ml (for Cry9Ca and Cry1Ia, …
Toxicity of several d-endotoxins of Bacillus thuringiensis against Helicoverpa armigera (Lepidoptera: Noctuidae) from Spain
2005
Abstract Toxicity and larval growth inhibition of 11 insecticidal proteins of Bacillus thuringiensis were evaluated against neonate larvae of Helicoverpa armigera, a major pest of important crops in Spain and other countries, by a whole-diet contamination method. The most active toxins were Cry1Ac4 and Cry2Aa1, with LC50 values of 3.5 and 6.3 μg/ml, respectively. At the concentrations tested, Cry1Ac4, Cry2Aa1, Cry9Ca, Cry1Fa1, Cry1Ab3, Cry2Ab2, Cry1Da, and Cry1Ja1, produced a significant growth inhibition, whereas Cry1Aa3, Cry1Ca2, and Cry1Ea had no effect.
Interactions between ecological traits and host plant type explain distribution change in noctuid moths.
2009
The ecological traits of species determine how well a species can withstand threats to which it is exposed. If these predisposing traits can be identified, species that are most at risk of decline can be identified and an understanding of the processes behind the declines can be gained. We sought to determine how body size, specificity of larval host plant, overwintering stage, type of host plant, and the interactions of these traits are related to the distribution change in noctuid moths. We used data derived from the literature and analyzed the effects of traits both separately and simultaneously in the same model. When we analyzed the traits separately, it seemed the most important deter…
Common receptor for Bacillus thuringiensis toxins Cry1Ac, Cry1Fa, and Cry1Ja in Helicoverpa armigera, Helicoverpa zea and Spodoptera exigua
2005
ABSTRACT Binding studies using 125 I-Cry1Ac and biotinylated Cry1Fa toxins indicate the occurrence of a common receptor for Cry1Ac, Cry1Fa, and Cry1Ja in Helicoverpa armigera , Helicoverpa zea , and Spodoptera exigua . Our results, along with previous binding data and the observed cases of cross-resistance, suggest that this pattern seems to be widespread among lepidopteran species.
High Bacterial Agglutination Activity in a Single-CRD C-Type Lectin from <em>Spodoptera exigua</em> (Lepidoptera: Noctuidae)
2017
Lectins are carbohydrate-interacting proteins that play a pivotal role in multiple physiological and developmental aspects of all organisms. They can specifically interact with different bacterial and viral pathogens through carbohydrate-recognition domains (CRD). In addition, lectins are also of biotechnological interest because of their potential use as biosensors for capturing and identifying bacterial species. In this work, three C-type lectins from the Lepidoptera Spodoptera exigua were produced as recombinant proteins and their bacterial agglutination properties were characterized. The lowest protein concentration producing bacterial agglutination against a panel of different Gram+ an…
The influence of smoke volatiles on sexual maturation and juvenile hormone biosynthesis in the black army cutworm, Actebia fennica (Lepidoptera: Noct…
2000
0965-1748 (Print) Journal Article Research Support, Non-U.S. Gov't; Outbreaks of the black army cutworm, Actebia fennica, are associated with recently burned sites, where larvae feed on early successional plants. In the present paper we show that smoke volatiles stimulate juvenile hormone biosynthesis in virgin females, resulting in a more rapid rate of oocyte maturation and a significant advance in the age of first calling (the release of the sex pheromone) compared to control females. The ecological implications of this physiological effect are discussed.
Antifeedant activity of neo-clerodane diterpenoids from Teucrium fruticans and derivatives of fruticolone
1999
The antifeedant activity of three neo-clerodane diterpenoids, fruticolone, isofruticolone and fruticolide from Teucrium fruticans was assessed using larvae of Spodoptera littoralis. Isofruticolone was one of the most potent of the Teucrium derived neo-clerodanes. Chemical modification of functional groups on fruticolone showed that its activity could be enhanced.